Inkjet printing has gained popularity in a number of printing applications. One of the growing applications is backlit display printing. A backlit display typically includes a thin transparent or light diffusing substrate or media on which an image is printed. During dark time an illumination source illuminates the substrate from its back (backlit). During daytime the sun illuminates the substrate. Backlit displays may be of different shapes such as flat panels, polygonal and round displays, and displays of arbitrary form. Roll-to-roll, drum or flatbed inkjet printers produce backlit displays. Flatbed printers print on rigid substrate. Roll-to-roll and drum printers print on a flexible substrate that is later attached to another transparent or light diffusing rigid substrate.
In order to reach the desired color saturation and density of the backlit display, the same image is printed on both the front side and the backside of the substrate. Another reason for this type of printing is the need to create the same visual appearance when the display is illuminated from the front side or the backside. The registration between the front side image and the backside image should be maintained with high accuracy, usually better than few tens of a millimeter.
Known prior art includes U.S. Pat. Nos. 6,352,332; 6,552,820 and US Patent Application Publication No. 2004/0139403.